Bradycardia and apnea in premature babies

In premature babies, apnea and bradycardia often occur with low blood oxygen levels. Apnea is a period when breathing stops and bradycardia is a slow heartbeat.

Apnea occurs first and the baby stops breathing. Since the baby is not breathing, the oxygen level in the blood will drop. The heart slows down due to low oxygen levels in the blood.

Together, apnea and bradycardia are often referred to as "As and B" or "episodes," and low oxygen levels in the blood are often referred to as desaturation or "desaturation."

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Oxygen saturation

Oxygen saturation measures the amount of hemoglobin that carries oxygen in the blood. The blood of a full-term baby, like the blood of a child or an adult, should be 95-100% oxygenated.

The blood of a premature baby receiving supplemental oxygen is generally kept at an oxygen saturation of 88% to 94%, not higher to prevent retinopathy of prematurity , a serious eye disease .

In a hospital, pulse oximetry is used to measure the amount of oxygen in the blood. When there is not enough oxygen in the blood, this is called desaturation . Discoloration can cause a bluish tint to the lips or skin, and can also lead to loss of tone or a "shaky" baby.


Apnea refers to the period in which breathing stops. In premature babies, apnea is any pause in breathing longer than 20 seconds that causes bradycardia or a decrease in the oxygen level in the baby's blood.

Premature babies have an immature nervous system and are prone to sleep apnea. Apnea sometimes causes a baby's heart to beat too slowly, called bradycardia.

In the intensive care unit, premature babies are hooked up to monitors that sound an alarm when their breathing has such long pauses. Usually a light pat on the back is all that is needed to remind the baby to breathe again, but sometimes babies need additional ventilation or oxygen when apnea.

Most premature babies will have overcome apnea when they are ready to go home, but some babies will still have recurrent episodes of mild apnea. If this happens, parents will bring their child home with an apnea monitor that will work if the child stops breathing.


Bradycardia means a slower than normal heart rate. In newborns, the heart rate is called bradycardia if it falls below 100 beats per minute in a baby weighing less than 1250 g (2 lb 12 oz) or below 80 beats per minute in an older baby.

When babies are in intensive care, their heart is monitored and episodes of bradycardia are treated with stimulation. If bradycardia continues, medications such as caffeine can be used to treat the condition.


Premature babies have various causes of apnea and bradycardia. Infection, anemia , and problems in the brain can cause As and B. However, the most common cause of apnea and bradycardia among premature babies in the intensive care unit is a condition called apnea of prematurity .

Apnea of prematurity is a condition caused by the immature nervous and muscular systems. Apnea of prematurity occurs more often in premature babies of a younger age; as gestational age decreases, apnea of prematurity increases.

Only 7% of babies born between 34 and 35 weeks have apnea of prematurity, but more than half of babies born between 30 and 31 weeks have this disease .

Apnea can occur because the process in the brain that tells the baby to breathe does not work and the baby stops breathing completely (central apnea), or because the baby's immature muscular system is not strong enough to maintain the airways. open airways and blocked airflow ( obstructive ) apnea ). Mixed central and obstructive sleep apnea also occurs.

Long-term effects

Doctors are not sure what the long-term effects of apnea and bradycardia are. They know that bradycardia causes a temporary drop in blood and oxygen levels in the brain.

They also know that premature babies who have had more days of reported apnea episodes have lower scores at 3 years on tests that measure development and neurological outcomes, but cannot say with certainty that apnea and bradycardia cause estimates. lower .

Doctors know for sure that apnea and bradycardia do not cause sudden infant death syndrome (SIDS).

Although premature babies tend to have a higher risk of SIDS than full-term babies, apnea in premature babies does not cause higher rates of SIDS.

Watch out

When babies in the intensive care unit have an episode of apnea or bradycardia, monitors that record their heart rate and breathing begin to sound an alarm. Sometimes the sound of the alarm is enough to stimulate the baby to breathe again, and the baby begins to breathe well before the nurse can react.

In other cases, an alarm is not enough. Stimulation will be used by rubbing or stroking the child. If the baby still does not recover, he will be given a bag and a mask to breathe.

Babies with frequent apnea can be given continuous positive airway pressure (CPAP) to help them breathe, or they can be artificially ventilated. Medications can also be used to treat apnea in prematurity.

Caffeine is a relatively new apnea treatment that has few side effects and has been very successful .

Preventing more spells

Knowing what causes sleep apnea and bradycardia can help nurses and parents minimize the number of seizures that premature babies experience. Apnea and bradycardia tend to occur when coming out of deep sleep , so it is important for babies to have long periods of deep sleep.

Coordinate your ICU visits with feeding and assessment times, and use quiet voices if you arrive at the unit while your baby is asleep. Temperature fluctuations in the incubator can also cause As and B, so try to maintain a stable temperature in the incubator by keeping the incubator doors as closed as possible.

Nipple feeding is another common cause of sleep apnea and bradycardia. When breastfeeding or bottle feeding a premature baby, stimulation is essential, especially at the beginning of the feeding.

If your baby feels like he is continuously sucking without stopping breathing, increase the rate of feeding by periodically removing the nipple from his mouth.

When will it disappear?

For most babies, sleep apnea starts to go away around the time they are supposed to be born and around the time they start to eat well enough on their own to consistently gain weight and keep a high temperature out of the box. incubator.

However, in some babies, apnea and bradycardia episodes will continue even after they are ready to leave the intensive care unit in any other way.

Most hospitals require babies to have a certain number of days without apnea or bradycardia before they can be discharged to ensure that they have fully overcome apnea of prematurity.

Babies who still have episodes of apnea or bradycardia, even after they are ready to go home in any other way, can be discharged from the hospital with an apnea monitor at home.

These monitors are controversial because they have not clearly demonstrated medical benefits and are difficult for parents to live with, but they are still widely used for children with persistent sleep apnea.

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